[llvm-commits] [llvm] r149187 - /llvm/trunk/include/llvm/ADT/BitVector.h

[Jakob Stoklund Olesen]

Author: stoklund
Date: Sat Jan 28 19:29:22 2012
New Revision: 149187

URL: http://llvm.org/viewvc/llvm-project?rev=149187&view=rev
Log:
Add a BitVector::reset(BitVector&) method.

The alternative LHS &= ~RHS is way too slow because it creates a
temporary that calls malloc/free.

Modified:
    llvm/trunk/include/llvm/ADT/BitVector.h

Modified: llvm/trunk/include/llvm/ADT/BitVector.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/BitVector.h?rev=149187&r1=149186&r2=149187&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/BitVector.h (original)
+++ llvm/trunk/include/llvm/ADT/BitVector.h Sat Jan 28 19:29:22 2012
@@ -318,6 +318,16 @@
     return *this;
   }
 
+  // reset - Reset bits that are set in RHS. Same as *this &= ~RHS.
+  BitVector &reset(const BitVector &RHS) {
+    unsigned ThisWords = NumBitWords(size());
+    unsigned RHSWords  = NumBitWords(RHS.size());
+    unsigned i;
+    for (i = 0; i != std::min(ThisWords, RHSWords); ++i)
+      Bits[i] &= ~RHS.Bits[i];
+    return *this;
+  }
+
   BitVector &operator|=(const BitVector &RHS) {
     if (size() < RHS.size())
       resize(RHS.size());